Sodium hydride → HCID 67564508, compound

Participants

Reaction Steps

3,4-Dimethylpyrrolo[2,3-b]carbazole-2-carboxylic acid (0.49 g, 1.76 mmol) and carbonyl diimidazole (0.33 g, 1.94 mmol) were dissolved in freshly distilled tetrahydrofuran (10 ml) in an oven-dried flask under a nitrogen atmosphere and this solution was stirred at room temperature for three hours. Meanwhile, in a second oven-dried flask, ethylamidoxime (0.39 g 4.43 mmol) was dissolved in THF (5 ml). To this was added crushed 3 Å sieves and the mixture was stirred at room temp for 45 min. Sodium hydride (60% dispersion in mineral oil, 0.142 g, 3.5 mmol) was added and the mixture stirred for a further 2.5 hours. The contents of the two flasks were combined (with further 10 ml THF) and stirred at room temp for 18 hours, by which time TLC showed complete consumption of the imidazolide intermediate. The solvent was removed in vacuo to give a yellow solid. Chromatography on silica (eluting with 25% ethyl acetate/hexane) gave the title compound as a yellow solid (0.150 g, 26%) with m.p. 258°-260° C. (decomp.). (Found: C, 72.03; H, 5.28; N, 16.42. C20H18N4O 0.08EtOAC requires: C, 72.33; H, 5.57; N, 16.60%); δH [2H6 ]-DMSO 11.55 (1H, s, 1-NH), 10.94 (1H, s, 9NH), 8.19 (1H, d, J 7.5, 5-H), 7.29-7.43 (2H, m, 7-H, 8-H), 7.22 (1H, s, 10-H), 7.13 (1H, ddd, J 8, 5.5, 2, 6-H), 3.20 and 3.03 (2×3H, 2×s, 3--CH3 and 4--CH3), 2.83 (2H, q, 7.5, CH2 CH3), 1.37 (3H, t, 7.5, CH2CH3); m/z (%) 330 (100, M+), 260 (34), 232 (29); νmax (KBr disk)/cm-1 3394, 1599, 1259.

Provenance & Evidence